This invention relates in general to sheet transport apparatus, and more particularly to a device for facilitating stacking of sheets in a hopper of a sheet transport apparatus.
In various sheet transport apparatus, it is a common requirement that sheets, travelling in stages along a travel path, be accurately located at some point in the path for effective transport in aligned relation to downstream process stations. For example, in certain transport apparatus, sheets are accumulated in a stack and, at a subsequent time, are fed from the accumulated stack to a downstream station. In some instances, the overall geometry of the transport apparatus necessitates that the sheets fed from the stack be fed in a direction substantially opposite to the direction of the sheets as they are directed for accumulation in the stack. This change in direction of the sheets in this portion of the transport cycle introduces complications into the transport apparatus construction in that proper alignment of the sheets in the stack at the feeder is necessary to assure the effective transport in aligned relation to the downstream process station.
Control of sheets directed to a stack is typically accomplished by a strip of material located to intercept the sheet travel path to the stack. Such strip of material, referred to as a dangler, serves to slow a sheet down as the sheet is directed at a relatively high speed to the stack. Danglers, however, are not generally capable of accurately aligning sheets in the stack relative to the mechanism for feeding sheets from the accumulated stack. A common device for accurately aligning sheets in the stack relative to the sheet feed mechanism includes a jogger which periodically tamps the edge of the sheet stack into accurate alignment with the feed mechanism. However, joggers are not generally used to stop sheet travel because when used in that manner they tend to damage the tamped edge of the individual sheets. Accordingly, in order to provide for sheet travel direction change and accurate stack alignment in a sheet transport of the type described above, a relatively complex arrangement is required which employs both danglers and joggers.